Tube enveloping plate condenser having rolled ends, and method of its construction



27,1956 .H. POLAD I TUBE ENVEILOPZNG TE CONQELNSER HAVING ROLLED ENDS, AND LETHOD pF'Irs' CONSTRUCTION 5 Sheetsheet l Filed Harchl5, 1951 INVENTOR.

27, 1956 1'. H. POLAD TUBE ENVELOPING PLATE CONDENSER HAVING'RQLLED ENDS, AND METHOD OF ITS CONSTRUCTION v Filed March 15, 1951 5 Slfeets-Sheet 2 INVENTOR. flay 45 /7f lad Nov. 27, 1956 1'. H. POLAD 2,772,077

TUBE ENVELQPING PLATE CONDENSER HAVING ROLLED ENDS, AND METHOD OF ITS CONSTRUCTION Filedrla'rch 15, 195]. 3 "5 SE OtS ShGEtA W gr/20 W xxx g 0 INVEN TOR. Tia/#45 M72 44 BY lj mlfivflw Nam. 27, 1956 T. H. POLAD' 2,772,077

TUBE ENVELOPING PLATE; CONDENSER HAVINGAROLLED' Filed larch 15,1951

IN VEN TOR.

HTTlF/YEY United States PatentO TUBE ENVELOPING PLATE CONDENSER HAVING ROLLED ENDS, AND PVHITHOD OF ITS CON- STRUCTION Thomas H. Polad, Dowagiac, Mich.,'assignor to Rudy Manufacturing Company, Dowagiac, Mich, a corporation of Michigan Application March 15, 1951, Serial No. 215,822

3 Claims. c1. 257-256) This invention relates generally to heat exchangers and the method of making the same and more particularly to a condenser having rolled ends and the method of its construction.

An object of this invention is to provide an improved heat exchanger of the character described.

Another object is to provide such an exchanger which is eflicient in operation and economical to manufacture.

Another object of this invention is to provide such an exchanger in which there is high rate of heat transfer between the fluid conveying conduit and the radiating surfaces.

Another object of this invention is to provide such a heat exchanger which eliminates the necessity for the laborious task of soldering or brazing the fluid conveying tubing to the radiating sheet material.

Another object of this invention is to provide such a heat exchanger in which the radiating plate material substantially completely surrounds and protects the fluid conveying conduit.

Another object of this invention is to provide such a heat exchanger in which the tubing may be secured to the sheet material member in a substantially planar state and which assembled tubing and sheet member may thereafter he formed to provide at least portions of four walls of a fluid conveying chimney.

Another object of this invention is to provide such a heat exchanger in which the portions of engagement between the tubing and sheet material member are substantially straight and all of the curved portions of the conduit member are external to the sheet material member.

Another object of this invention is to provide such a chimney forming heat exchanger in which portions of the top side walls are cut away to provide for fluid flow through the chimney even though the top opening may be otherwise restricted.

A further object of this invention is to provide a new and improved method for making such heat exchanger.

Another object of this invention is to provide a method for making such an exchanger in which the operation of securing the tubing to the sheet metal member may be easily and economically accomplished.

Another object of this invention is to provide such a securing method which may be accomplished in a pressing operation.

Another object of this invention is to provide a novel method for wrapping a sheet material member substantially completely around a second elongated member to provide a tight mechanical joint therebetween.

Another object of this invention is to provide a new and novel method of wrapping an otherwise planar sheet ice Fig. 2 is a lower end view of the condenser of Fig. 1;

Fig. 3 is a left-hand side view of the condenser of Fig. 1;

Fig. 4 is a fractional view of the condenser taken substantially along the lines 44 of Fig. l;

Fig. 5 is a fractional view similar to Fig. 1 showing a modified form of the condenser embodying the invention;

Fig. 6 is a view partially in section showing the method for initially rolling the grooves in the sheet material;

Fig. 7 is a fractional view taken substantially along the lines 77 of Fig. 6;

Fig. 8 is a partial view in plan of the sheet metal struc ture at an intermediate step in the process of manufacture showing the sheet material member with the V grooves rolled therein and showing the notched out corner portions for providing the escape vents; V

Fig. 9 is a partial view in top plan of the lower shearing die for cutting out the notched portions shown in Fig. 8;

Fig. 10 is a partial view in elevation showing both notching dies;

Fig. 11 is a view taken substantially along the lines 1111 of Fig. 10;

Fig. 12 is a plan view showing the bottom die used for wrapping the sheet metal about the tubing within the grooves;

Fig. 13 is a view taken substantially along the lines 1313 of Fig. 12 and showing the dies and sheet material with the press in a position just subsequentto the engagement of the top die with the workpiece;

Fig 14 is a view similar to Fig. 13 but showing the die in a final or closed position with the sheet material wrapped about the tubing;

Fig. 15 is an enlarged fragmentary view within the dot-dash circle 15 of Fig. 13 showing the tubing within the grooves of the sheet metal member at the start of the operation for wrapping the sheet metal about the tubing;

Fig. 16 is a view similar to Fig. 15 but showing an intermediate step in the process of wrapping the sheet material about the tubing; I

Fig. 17 is a view similar toFig. 16-but showing the closed position of the dies with the sheet material wrapped substantially completely about the tubular member;

Fig. 18 is a partial view in plan of the sheet metal member after it has been wrapped around the tubing;

Fig. 19 is a partial view in elevation with portions shown in section showing the die for rolling the end of portions of the heat exchanger; and

Fig. 20 is an end view of the end rolling die showing a portion of the heat exchanger therein in dot-dash lines.

Generically, this invention is directed toward a sheet metal heat exchanger and its method of manufacture which among other uses may be used as a refrigeration condenser and attached to an external wall of the refrigerated cabinet for providing a natural draft fluid flow chimney by which the heat from the condensing unit may be radiated into the ambient atmosphere.

More specifically, the condenser 1 comprises a sheet metal member 2 which has been provided with a plurality of transversely extending grooves 4 in which are positioned horizontally extending portion 6 of a generally vertically leading endless conduit 8 having an inlet end 10 and an outlet end 12. The conduit 8, in'the form shown, comprises a single piece of tubing in which the plurality of horizontally extending portions embedded in the grooves 4 of the sheet metal member 2 are connected together by return bends 14. The sheet metal member 2 is preferably of one piece construction and comprises a substantially planar main or wall portion 16 and laterally extending side portions 18. These side portions 1 8 preferably may be and are shown as rebent V side portions of'the sheet metal member'Z which provide a substantially semi-cylindrical portion 20 and 'a short substantially.planarrportion 22 which extends ina plane parallel'to but spaeed'from the. plane of'the main portion '16. The portions 22 maybe provided with suitable apertures 24. for receivingsecuring bolts 26by which the condenser 1 maybe attached to the refrigeratorcabinet electric refrigerator, which when used is often located underneath an overhanging cupboard or shelf which might tend to restrict fluid flowupwardly there throug h and out its upper open end. For -this reason,'the upper end .portions of the planar-portions 22 and adjacent portionsof the semicylindricalf-portions 20am cut away to provide side openings or notehes 2i8 in the laterally extending walls -18=to permit fiow of-fluid outwardly therethrough from the interior of the chimney-type ev'aps orator p 7 a As will be seen in:Fig. 4, the;sheetmetalmember-l is wrapped substantially completely around the conduit portions 6 in a manner to form a tight mechanicalconnection therebetween which does not require soldering or brazing and to provide a pleasing appearing substantially planar exterior 'wall-30-for the evaporatorl. The substantially completely wrapping; of thesheet metal memher 2 about the tubing 6 provides a maximum of -heat transfer surface ,therebetween. Also,'since the tubing 6, in manyinstances, is of a softenmaterial than thatof the sheetmaterial 2,;the sheetzmaterial 2 acts as a mechanical reinforcement for the wallsof'the tubing 6. V -In-Fig 5 there-is shown a modified form of'evaporator lA- in which a singlesheet-material-member 2A-is provided with a plurality of independent continuous conduits -8 A and -8B which'are provided'with inlets 10A and-10B respectively and outlets. Theoutlet-for the conduit'SA is not-shown while theoutlet for the-conduit 8B is shown at 12B. The relative-amounts of the sheet metal material 2 with which the conduits 8A and 8B are associated and the consequentlengths of the conduits 8A andSB may be variedinanydesired proportion de pending upon the relative amounts of, and the-temperatureof, the heat to be'radiated-from the systems'to which they are connected. 7 a

The-novel preferred method ofmanufacturing the foregoing described evaporator 1 is described below with reference to Figs -6 through 20. V 7

Referring to Fig. 6, astrip of sheet metal, of any desired length and of a width equal to the height of the desired evaporator 1, may be suit-ably fed through-a series of corrugating'work rolls'50 which will progressively form a series of depressions in the sheet metal resulting :in the grooves 4. After the grooves *4 have been; formed in thesheet metal,-itis cut to proper lengths in suitableshearing dies not shown to provide a length of metal whichis equal to-the developed width of the sheet "metal *2. A preferred method is to ;cut the flat sheet metal -to-the developed -width-and to corrugate such cut lengths since fiat metal is nrore easily sheared and requires no expensive-dies. Subsequentl'y'the sheet of the desireddimensionis inserted :in the notchingdie to have two opposite corner portions "cut away to providenotches 28. 7 r V 'Eigsv'9, 10 and 11 show aportion of such punch-and die set which will 1 cut away the upper corners to provide the notches PZS-as shown in -Fig.f8. Preferably thelpunch and die set comprises -an dipper movable ;punch 60 anda lower die 62 which have spaced cuttingor shearing sportions spaced apart the desired distance to shear -both notches lii at once. Since the-Spaced shearing -;portions. are alike except that one is' a mirror arrangement of the other, only one shearingjportion is shown to'siinplify the disclosure. :Ifvarious sized 'evaporators are to be,

made, the right and left shearing portions could be rela 'tivly movable or could'be in separate presses and the right and left notches could be sheared in separate operations. The particular arrangement actually used will de: pend upon the relative economies of labor and tooling costs.

7 The illustratedmight-hand shearing portion-comprises the upper right-hand portion of the punch 60 arid lower die 62. The lower die is provided with -an upward extending stop 64 against which the upper end surface 'of the sheet metaImembenZispositioned'with the-grooves 4 therein lying within upwardly facing eonipl'ementary J grooves 66 in a pad 67 of the lower'diemer'nber 62. The

. face/76 ofKthe-mainportion of the block 72. The faces top ended'ge-of'the member Z engages a stop 6 9'carried by the die 62 inter mediatethe shearing portions. The stops 66 and 69 therefore act t'ol'cicate' the member 2 in the punch and die set. The punch member is provided 'witha resiliently mountedpad 68 which, upon downward movement of thetpunch 60, will" engage the upper surface of the sheet metal-member ZSfor securingly holding it-to the lower die member 62. Continued downward movement-of the punch6 0 is permitted-by resilient springs 70 which urge the-pads 68 inadownward direction from the punch-60 but-permit-relative movement'of the punch 60 subsequent-to engagement ofthe pad 68 withthe workpiece. t

The; punch 60 is; provided with; a pair of shearingblocks 72 and--73. The block72-hasa series of downwardly extending V-shaped projections 74 having an end shearing f-ace'75 which is in-thesameplane-as-the end shearing 75 and 76 cooperatewith-anend shearing face 77 of pad 67 carried by the die 62. Upon downward move-f ment=of the punch 60-theprojections 74 movedown into the V :grooves 4 in the sheet metal member -2"and the shearing edges-or faces -75 and-76 pass downwardly closely adjacent the shearing face 77 to shear away-a sectionof the 'mem b'er transversely' of the 1 grooves 4. The shear; block 73 cooperates similarly witha lower shear block 78 to-shear-the member parallel to thegrooves 4-whereby a corner :portion -of the member 2 is -'cut away to form th'ecutout notch 28.

Subsequent to notching ofthe'workpiece a length of suitable tubing, 'whi'ch has-previously been 'rebent upon itself a number of-times to form 'aseries spaced sub st'antially parallel extendingportionsconnected at their end portions 'by rebentip'ortions to providethe conduit portions 6 and 14,-is laid within the V-shaped grooves 4.

Y The assembly so made is then placed in another press-on topofthe lowerrdie member thereof substantially as shown in Fig. 13. 4

The lower die member 100 is provided-with a plurality =of- 1'novable-die blocks 102 extending substantially completely across the die and which a're urged upwardly by -means of. springs 104. Upward movement thereof is limited byen'ga'gement'of theheads 106 of screws 108 which are -screw=threadecl into the 'die blocks 102' and extend downwardly through the. lower die in apertures 110. The lower end portions of the apertures 1 10 are of enlarged diameter for-receiving the head 106 and'providing a shoulder 112 against which the upwardly fac ing shoulderof the head 106 engages to limit upward movement of the die blocks 102. Intermediate "each of-thedie blocks102, the lower die 100'carries'a fixed' die block -114'having'an upwardly facing concave :sur-

102 is substantially that of the outer 'di'ameter 'of the sheet metal member when wrapped tightly to the conduit or tubing as shown in Figs. 16 and 17. The grooves 4 as initially formed by the rolls 50, are of somewhat greater width than the space between the movable die blocks 102. The die blocks 102 are therefore arranged in two alternating groups of blocks 102a and 102b. The blocks 102a are arranged to have less upward movement and normally held at a lower level than the blocks 1021:.

When the member 2 is initially placed in the die 100 it rests in the die blocks 102b with the grooves 4 extending partially into the space between the blocks 102a shown in Figs. 13 and 15. As the upper die 120, which has a planar lower surface, moves downwardly, the upwardly-most set of the movable die blocks 102 will move downward therewith moving the grooves 4 down into the spaces between the die blocks 102 toward the fixed die blocks 114. This forces the grooves 4 into these narrower spaces pressing them tightly about the lower half of the conduit. At the time the upper die 120 has moved the workpiece so that it engages the top surface of the lowerly positioned die blocks 102a, the lower end surface of the grooves 4 will be in engagement with the upper concave surfaces 116 of the fixed die blocks 114. The force exerted by the springs 104 on the die blocks 102a is sufiicient to hold the blocks 102a against downward movement and to wrap the sheet metal about the lower half of the conduits. At the position shown in Fig. 16 in which the planar portion of the member 2 has just engaged the blocks 102a, the blocks 102a are still in this uppermost position. Continued downward movement of the upper die 120 will force the movable die blocks 102 downward but since the bottom end of the groove 4 is already engaging the upper surface of the fixed die blocks 114, the excess metal in the upper leg portions of the groove 4 will be pushed about the surface of the conduit and when the press has been fully closed, as shown in Fig. 14, the metal will have wrapped itself around the tubing substantially as shown in Fig. 17.

Up to this time the sheet metal member is in substantially planar form and ready to have its side edges rolled in the rolling dies shown in Figs. 19 and 20. Initially the upper die 200 is in an upper position to permit the sheet metal member 2 to be placed therein with the side edge in engagement with a longitudinally extending stop 202. The upper die is then moved down by suitable mechanism to move the resiliently supported clamping pad 203 to clamp the member 2 against the lower die 204. Continued downward movement moves the lower concave substantially semi-cylindrical surface 205 of the die 200 downwardly to wrap the side edge of the sheet metal member 2 about the lower upwardly facing convex substantially semi-cylindrical surface 206 of the fixed die 204. In this regard it should be noted that the convex surface of said die 204 is provided with grooves 207 which receives the grooves 4 of the sheet member 2 whereby the walls thereof and of the conduit 8 will be held against unwanted distortion. The dies 200 and 204 thus rebend the side edge of the condenser about itself to form the laterally extending end wall 18 comprising the semi-cylindrical portion 20 and the substantially planar portion 22.

The apertures 24 may be made at any desired time such as concurrently with the shearing of the strip to proper dimension. While there is shown and described only limited forms of the invention, it is to be appreciated that the specific details may be varied widely and still come within the scope of my invention which is to be limited only by the scope of the hereinafter appended claims.

What is claimed and is desired to be secured by United States Letters Patent is as follows:

1. In a plate-type heat exchanger, a sheet metal member formed to provide a substantially main planar portion, and rebent curved side members extending laterally from the plane of said main portion and into a plane spaced from the plane of said main portion, said portions in said spaced plane being provided with means for securing such exchanger to a vertical surface, said sheet metal member being deformed to provide spaced substantially parallel channels extending laterally completely across said sheet metal member inwardly from the outer surface thereof to provide fiat webs therebetween, an endless conduit having spaced portions positioned within said channels and U-shaped portions connecting said spaced portions and positioned in spaced relation to said sheet metal member in said spaced plane, the interior Walls of said channels engaging the walls of said spaced conduit portions and being formed therearcund to present a smooth outer surface to said exchanger.

2. In a plate-type heat exchanger; a sheet metal member formed to provide a substantially planar main portion, and bent side members extending laterally from the plane of said main portion, said side members being provided with means for securing such exchanger to a surface with said main portion spaced therefrom, said sheet metal member being deformed to provide spaced substantially parallel channels extending laterally completely across said sheet metal member inwardly from the outer surface thereof to provide flat webs therebetween, an endless conduit having spaced portions positioned within said chan nels and U-shaped portions connecting said spaced portions and positioned in spaced relation to said sheet metal member in said side members, the interior walls of said channels engaging the walls of said spaced conduit portions and being formed therearound to present a smooth outer surface to said exchanger.

3. The method of making a tube and plate heat exchanger from a length of conduit and a section of substantially fiat sheet metal which comprises the steps of: forming spaced trough means in said sheet metal section extending completely across one dimension thereof while maintaining flat webs disposed between the trough means and keeping said webs in a common plane, form-ing said conduit to have straight portions joined by end loop portions, placing the straight portions of said formed conduit in said trough means with the end loop portions extending therebeyond, of supporting the walls of said trough means against movement outwardly away from each other, confining the webs at the ends of said walls against movement out of said plane, and applying a force to said troughs to move the bottom of the trough means toward the plane of said webs and thereby collapse the walls of the trough means inwardly to cause the inner portions thereof to wrap around the periphery of the straight portion of the conduit, and limiting the movement of the outer portions of said trough walls to said plane to thereby provide -a substantially continuous flat surface to one side of said exchanger.

References Cited in the file of this patent UNITED STATES PATENTS 23,599 Montgomery Apr. 12, 1859 1,771,268 Musgrave July 22, 1930 2,029,891 Newman Feb. 4, 1936 2,091,584 Brown Aug. 31, 1937 2,190,288 Higham Feb. 13, 1940 2,271,437 Lewis Jan. 27, 1942 2,279,272 Anderson Apr. 7, 1942 2,281,299 Steenstrup Apr. 28, 1942 2,289,685 Schoen' July 14, 1942 2,538,014 Kleist Jan. 16, 1951 2,585,043 Sandberg Feb. 12, 1952 2,646,259 Powell July 21, 1953 2,660,412 Sandberg Nov. 24, 1953 2,661,191 Sandberg Dec. 1, 1953 

